dom/animation/Animation.cpp
author AndiAJ <andiaj@users.noreply.github.com>
Wed, 25 Sep 2024 15:14:32 +0000 (9 months ago)
changeset 835109 51b5f898b64a5839a0714c3251ccb6dc6131aa17
parent 821446 905d7610caf3eeca29029173dfb718321ae2ebdb
child 845814 a5ae29b1732397bd4636a72cdbb4ec508375ddaf
permissions -rw-r--r--
Bug 1916749 - Add set as default prompt settings helper and use it only where needed in UI tests r=aaronmt, a=dsmith With the changes done in [[ https://bugzilla.mozilla.org/show_bug.cgi?id=1911100 | 1911100 ]] Gela wanted to display the "Set as default browser" native prompt in home fragment. The changes were backed out because addPrivateBrowsingShortcutFromHomeScreenCFRTest started to fail all of a sudden. The UI test failed because the "Set as default browser" native prompt was displayed when performing the second switch to private browsing while trying to trigger the "Add private browsing shortcut" prompt. To overcome this problem I've added a settings helper to disable it by default and use it where needed. All UI tests successfully passed 3x on Firebase ✅ And I've also did a [[ https://firefox-ci-tc.services.mozilla.com/tasks/eMjCXxH1S2Kvmd3xdKYTNQ/runs/0/logs/public/logs/live.log | try run ]] with Gela's changes and addPrivateBrowsingShortcutFromHomeScreenCFRTest successfully passed 50x on Firebase ✅ (after landing these changes she can try to land her changes again) Original Revision: https://phabricator.services.mozilla.com/D221038 Differential Revision: https://phabricator.services.mozilla.com/D223604
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "Animation.h"

#include "mozilla/Likely.h"
#include "nsIFrame.h"
#include "AnimationUtils.h"
#include "mozAutoDocUpdate.h"
#include "mozilla/dom/AnimationBinding.h"
#include "mozilla/dom/Document.h"
#include "mozilla/dom/DocumentInlines.h"
#include "mozilla/dom/DocumentTimeline.h"
#include "mozilla/dom/MutationObservers.h"
#include "mozilla/dom/Promise.h"
#include "mozilla/AnimationEventDispatcher.h"
#include "mozilla/AnimationTarget.h"
#include "mozilla/AutoRestore.h"
#include "mozilla/CycleCollectedJSContext.h"
#include "mozilla/DeclarationBlock.h"
#include "mozilla/Maybe.h"  // For Maybe
#include "mozilla/StaticPrefs_dom.h"
#include "nsAnimationManager.h"  // For CSSAnimation
#include "nsComputedDOMStyle.h"
#include "nsDOMMutationObserver.h"    // For nsAutoAnimationMutationBatch
#include "nsDOMCSSAttrDeclaration.h"  // For nsDOMCSSAttributeDeclaration
#include "nsThreadUtils.h"  // For nsRunnableMethod and nsRevocableEventPtr
#include "nsTransitionManager.h"  // For CSSTransition
#include "ScrollTimelineAnimationTracker.h"

namespace mozilla::dom {

// Static members
uint64_t Animation::sNextAnimationIndex = 0;

NS_IMPL_CYCLE_COLLECTION_INHERITED(Animation, DOMEventTargetHelper, mTimeline,
                                   mEffect, mReady, mFinished)

NS_IMPL_ADDREF_INHERITED(Animation, DOMEventTargetHelper)
NS_IMPL_RELEASE_INHERITED(Animation, DOMEventTargetHelper)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(Animation)
NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)

JSObject* Animation::WrapObject(JSContext* aCx,
                                JS::Handle<JSObject*> aGivenProto) {
  return dom::Animation_Binding::Wrap(aCx, this, aGivenProto);
}

// ---------------------------------------------------------------------------
//
// Utility methods
//
// ---------------------------------------------------------------------------

namespace {
// A wrapper around nsAutoAnimationMutationBatch that looks up the
// appropriate document from the supplied animation.
class MOZ_RAII AutoMutationBatchForAnimation {
 public:
  explicit AutoMutationBatchForAnimation(const Animation& aAnimation) {
    NonOwningAnimationTarget target = aAnimation.GetTargetForAnimation();
    if (!target) {
      return;
    }

    // For mutation observers, we use the OwnerDoc.
    mAutoBatch.emplace(target.mElement->OwnerDoc());
  }

 private:
  Maybe<nsAutoAnimationMutationBatch> mAutoBatch;
};
}  // namespace

// ---------------------------------------------------------------------------
//
// Animation interface:
//
// ---------------------------------------------------------------------------

Animation::Animation(nsIGlobalObject* aGlobal)
    : DOMEventTargetHelper(aGlobal),
      mAnimationIndex(sNextAnimationIndex++),
      mRTPCallerType(aGlobal->GetRTPCallerType()) {}

Animation::~Animation() = default;

/* static */
already_AddRefed<Animation> Animation::ClonePausedAnimation(
    nsIGlobalObject* aGlobal, const Animation& aOther, AnimationEffect& aEffect,
    AnimationTimeline& aTimeline) {
  // FIXME: Bug 1805950: Support printing for scroll-timeline once we resolve
  // the spec issue.
  if (aOther.UsingScrollTimeline()) {
    return nullptr;
  }

  RefPtr<Animation> animation = new Animation(aGlobal);

  // Setup the timeline. We always use document-timeline of the new document,
  // even if the timeline of |aOther| is null.
  animation->mTimeline = &aTimeline;

  // Setup the playback rate.
  animation->mPlaybackRate = aOther.mPlaybackRate;

  // Setup the timing.
  const Nullable<TimeDuration> currentTime = aOther.GetCurrentTimeAsDuration();
  if (!aOther.GetTimeline()) {
    // This simulates what we do in SetTimelineNoUpdate(). It's possible to
    // preserve the progress if the previous timeline is a scroll-timeline.
    // So for null timeline, it may have a progress and the non-null current
    // time.
    if (!currentTime.IsNull()) {
      animation->SilentlySetCurrentTime(currentTime.Value());
    }
    animation->mPreviousCurrentTime = animation->GetCurrentTimeAsDuration();
  } else {
    animation->mHoldTime = currentTime;
    if (!currentTime.IsNull()) {
      // FIXME: Should we use |timelineTime| as previous current time here? It
      // seems we should use animation->GetCurrentTimeAsDuration(), per
      // UpdateFinishedState().
      const Nullable<TimeDuration> timelineTime =
          aTimeline.GetCurrentTimeAsDuration();
      MOZ_ASSERT(!timelineTime.IsNull(), "Timeline not yet set");
      animation->mPreviousCurrentTime = timelineTime;
    }
  }

  // Setup the effect's link to this.
  animation->mEffect = &aEffect;
  animation->mEffect->SetAnimation(animation);

  animation->mPendingState = PendingState::PausePending;

  // We expect our relevance to be the same as the orginal.
  animation->mIsRelevant = aOther.mIsRelevant;

  animation->PostUpdate();
  animation->mTimeline->NotifyAnimationUpdated(*animation);
  return animation.forget();
}

NonOwningAnimationTarget Animation::GetTargetForAnimation() const {
  AnimationEffect* effect = GetEffect();
  NonOwningAnimationTarget target;
  if (!effect || !effect->AsKeyframeEffect()) {
    return target;
  }
  return effect->AsKeyframeEffect()->GetAnimationTarget();
}

/* static */
already_AddRefed<Animation> Animation::Constructor(
    const GlobalObject& aGlobal, AnimationEffect* aEffect,
    const Optional<AnimationTimeline*>& aTimeline, ErrorResult& aRv) {
  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());

  AnimationTimeline* timeline;
  Document* document =
      AnimationUtils::GetCurrentRealmDocument(aGlobal.Context());

  if (aTimeline.WasPassed()) {
    timeline = aTimeline.Value();
  } else {
    if (!document) {
      aRv.Throw(NS_ERROR_FAILURE);
      return nullptr;
    }
    timeline = document->Timeline();
  }

  RefPtr<Animation> animation = new Animation(global);
  animation->SetTimelineNoUpdate(timeline);
  animation->SetEffectNoUpdate(aEffect);

  return animation.forget();
}

void Animation::SetId(const nsAString& aId) {
  if (mId == aId) {
    return;
  }
  mId = aId;
  MutationObservers::NotifyAnimationChanged(this);
}

void Animation::SetEffect(AnimationEffect* aEffect) {
  SetEffectNoUpdate(aEffect);
  PostUpdate();
}

// https://drafts.csswg.org/web-animations/#setting-the-target-effect
void Animation::SetEffectNoUpdate(AnimationEffect* aEffect) {
  RefPtr<Animation> kungFuDeathGrip(this);

  if (mEffect == aEffect) {
    return;
  }

  AutoMutationBatchForAnimation mb(*this);
  bool wasRelevant = mIsRelevant;

  if (mEffect) {
    // We need to notify observers now because once we set mEffect to null
    // we won't be able to find the target element to notify.
    if (mIsRelevant) {
      MutationObservers::NotifyAnimationRemoved(this);
    }

    // Break links with the old effect and then drop it.
    RefPtr<AnimationEffect> oldEffect = mEffect;
    mEffect = nullptr;
    if (IsPartialPrerendered()) {
      if (KeyframeEffect* oldKeyframeEffect = oldEffect->AsKeyframeEffect()) {
        oldKeyframeEffect->ResetPartialPrerendered();
      }
    }
    oldEffect->SetAnimation(nullptr);

    // The following will not do any notification because mEffect is null.
    UpdateRelevance();
  }

  if (aEffect) {
    // Break links from the new effect to its previous animation, if any.
    RefPtr<AnimationEffect> newEffect = aEffect;
    Animation* prevAnim = aEffect->GetAnimation();
    if (prevAnim) {
      prevAnim->SetEffect(nullptr);
    }

    // Create links with the new effect. SetAnimation(this) will also update
    // mIsRelevant of this animation, and then notify mutation observer if
    // needed by calling Animation::UpdateRelevance(), so we don't need to
    // call it again.
    mEffect = newEffect;
    mEffect->SetAnimation(this);

    // Notify possible add or change.
    // If the target is different, the change notification will be ignored by
    // AutoMutationBatchForAnimation.
    if (wasRelevant && mIsRelevant) {
      MutationObservers::NotifyAnimationChanged(this);
    }
  }

  MaybeScheduleReplacementCheck();

  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);
}

void Animation::SetTimeline(AnimationTimeline* aTimeline) {
  SetTimelineNoUpdate(aTimeline);
  PostUpdate();
}

// https://drafts.csswg.org/web-animations/#setting-the-timeline
void Animation::SetTimelineNoUpdate(AnimationTimeline* aTimeline) {
  if (mTimeline == aTimeline) {
    return;
  }

  StickyTimeDuration activeTime =
      mEffect ? mEffect->GetComputedTiming().mActiveTime : StickyTimeDuration();

  const AnimationPlayState previousPlayState = PlayState();
  const Nullable<TimeDuration> previousCurrentTime = GetCurrentTimeAsDuration();
  // FIXME: The definition of end time in web-animation-1 is different from that
  // in web-animation-2, which includes the start time. We are still using the
  // definition in web-animation-1 here for now.
  const TimeDuration endTime = TimeDuration(EffectEnd());
  double previousProgress = 0.0;
  if (!previousCurrentTime.IsNull() && !endTime.IsZero()) {
    previousProgress =
        previousCurrentTime.Value().ToSeconds() / endTime.ToSeconds();
  }

  RefPtr<AnimationTimeline> oldTimeline = mTimeline;
  if (oldTimeline) {
    oldTimeline->RemoveAnimation(this);
  }

  mTimeline = aTimeline;

  mResetCurrentTimeOnResume = false;

  if (mEffect) {
    mEffect->UpdateNormalizedTiming();
  }

  if (mTimeline && !mTimeline->IsMonotonicallyIncreasing()) {
    // If "to finite timeline" is true.

    ApplyPendingPlaybackRate();
    Nullable<TimeDuration> seekTime;
    if (mPlaybackRate >= 0.0) {
      seekTime.SetValue(TimeDuration());
    } else {
      seekTime.SetValue(TimeDuration(EffectEnd()));
    }

    switch (previousPlayState) {
      case AnimationPlayState::Running:
      case AnimationPlayState::Finished:
        mStartTime = seekTime;
        break;
      case AnimationPlayState::Paused:
        if (!previousCurrentTime.IsNull()) {
          mResetCurrentTimeOnResume = true;
          mStartTime.SetNull();
          mHoldTime.SetValue(
              TimeDuration(EffectEnd().MultDouble(previousProgress)));
        } else {
          mStartTime = seekTime;
        }
        break;
      case AnimationPlayState::Idle:
      default:
        break;
    }
  } else if (oldTimeline && !oldTimeline->IsMonotonicallyIncreasing() &&
             !previousCurrentTime.IsNull()) {
    // If "from finite timeline" and previous progress is resolved.
    SetCurrentTimeNoUpdate(
        TimeDuration(EffectEnd().MultDouble(previousProgress)));
  }

  if (!mStartTime.IsNull()) {
    mHoldTime.SetNull();
  }

  if (!aTimeline) {
    MaybeQueueCancelEvent(activeTime);
  }

  UpdateScrollTimelineAnimationTracker(oldTimeline, aTimeline);

  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);

  // FIXME: Bug 1799071: Check if we need to add
  // MutationObservers::NotifyAnimationChanged(this) here.
}

// https://drafts.csswg.org/web-animations/#set-the-animation-start-time
void Animation::SetStartTime(const Nullable<TimeDuration>& aNewStartTime) {
  // Return early if the start time will not change. However, if we
  // are pending, then setting the start time to any value
  // including the current value has the effect of aborting
  // pending tasks so we should not return early in that case.
  if (!Pending() && aNewStartTime == mStartTime) {
    return;
  }

  AutoMutationBatchForAnimation mb(*this);

  Nullable<TimeDuration> timelineTime;
  if (mTimeline) {
    // The spec says to check if the timeline is active (has a resolved time)
    // before using it here, but we don't need to since it's harmless to set
    // the already null time to null.
    timelineTime = mTimeline->GetCurrentTimeAsDuration();
  }
  if (timelineTime.IsNull() && !aNewStartTime.IsNull()) {
    mHoldTime.SetNull();
  }

  Nullable<TimeDuration> previousCurrentTime = GetCurrentTimeAsDuration();

  ApplyPendingPlaybackRate();
  mStartTime = aNewStartTime;

  mResetCurrentTimeOnResume = false;

  if (!aNewStartTime.IsNull()) {
    if (mPlaybackRate != 0.0) {
      mHoldTime.SetNull();
    }
  } else {
    mHoldTime = previousCurrentTime;
  }

  CancelPendingTasks();
  if (mReady) {
    // We may have already resolved mReady, but in that case calling
    // MaybeResolve is a no-op, so that's okay.
    mReady->MaybeResolve(this);
  }

  UpdateTiming(SeekFlag::DidSeek, SyncNotifyFlag::Async);
  if (IsRelevant()) {
    MutationObservers::NotifyAnimationChanged(this);
  }
  PostUpdate();
}

// https://drafts.csswg.org/web-animations/#current-time
Nullable<TimeDuration> Animation::GetCurrentTimeForHoldTime(
    const Nullable<TimeDuration>& aHoldTime) const {
  Nullable<TimeDuration> result;
  if (!aHoldTime.IsNull()) {
    result = aHoldTime;
    return result;
  }

  if (mTimeline && !mStartTime.IsNull()) {
    Nullable<TimeDuration> timelineTime = mTimeline->GetCurrentTimeAsDuration();
    if (!timelineTime.IsNull()) {
      result = CurrentTimeFromTimelineTime(timelineTime.Value(),
                                           mStartTime.Value(), mPlaybackRate);
    }
  }
  return result;
}

// https://drafts.csswg.org/web-animations/#set-the-current-time
void Animation::SetCurrentTime(const TimeDuration& aSeekTime) {
  // Return early if the current time has not changed. However, if we
  // are pause-pending, then setting the current time to any value
  // including the current value has the effect of aborting the
  // pause so we should not return early in that case.
  if (mPendingState != PendingState::PausePending &&
      Nullable<TimeDuration>(aSeekTime) == GetCurrentTimeAsDuration()) {
    return;
  }

  AutoMutationBatchForAnimation mb(*this);

  SetCurrentTimeNoUpdate(aSeekTime);

  if (IsRelevant()) {
    MutationObservers::NotifyAnimationChanged(this);
  }
  PostUpdate();
}

void Animation::SetCurrentTimeNoUpdate(const TimeDuration& aSeekTime) {
  SilentlySetCurrentTime(aSeekTime);

  if (mPendingState == PendingState::PausePending) {
    // Finish the pause operation
    mHoldTime.SetValue(aSeekTime);

    ApplyPendingPlaybackRate();
    mStartTime.SetNull();

    if (mReady) {
      mReady->MaybeResolve(this);
    }
    CancelPendingTasks();
  }

  UpdateTiming(SeekFlag::DidSeek, SyncNotifyFlag::Async);
}

// https://drafts.csswg.org/web-animations/#set-the-playback-rate
void Animation::SetPlaybackRate(double aPlaybackRate) {
  mPendingPlaybackRate.reset();

  if (aPlaybackRate == mPlaybackRate) {
    return;
  }

  AutoMutationBatchForAnimation mb(*this);

  Nullable<TimeDuration> previousTime = GetCurrentTimeAsDuration();
  mPlaybackRate = aPlaybackRate;
  if (!previousTime.IsNull()) {
    SetCurrentTime(previousTime.Value());
  }

  // In the case where GetCurrentTimeAsDuration() returns the same result before
  // and after updating mPlaybackRate, SetCurrentTime will return early since,
  // as far as it can tell, nothing has changed.
  // As a result, we need to perform the following updates here:
  // - update timing (since, if the sign of the playback rate has changed, our
  //   finished state may have changed),
  // - dispatch a change notification for the changed playback rate, and
  // - update the playback rate on animations on layers.
  UpdateTiming(SeekFlag::DidSeek, SyncNotifyFlag::Async);
  if (IsRelevant()) {
    MutationObservers::NotifyAnimationChanged(this);
  }
  PostUpdate();
}

// https://drafts.csswg.org/web-animations/#seamlessly-update-the-playback-rate
void Animation::UpdatePlaybackRate(double aPlaybackRate) {
  if (mPendingPlaybackRate && mPendingPlaybackRate.value() == aPlaybackRate) {
    return;
  }

  // Calculate the play state using the existing playback rate since below we
  // want to know if the animation is _currently_ finished or not, not whether
  // it _will_ be finished.
  AnimationPlayState playState = PlayState();

  mPendingPlaybackRate = Some(aPlaybackRate);

  if (Pending()) {
    // If we already have a pending task, there is nothing more to do since the
    // playback rate will be applied then.
    //
    // However, as with the idle/paused case below, we still need to update the
    // relevance (and effect set to make sure it only contains relevant
    // animations) since the relevance is based on the Animation play state
    // which incorporates the _pending_ playback rate.
    UpdateEffect(PostRestyleMode::Never);
    return;
  }

  AutoMutationBatchForAnimation mb(*this);

  if (playState == AnimationPlayState::Idle ||
      playState == AnimationPlayState::Paused ||
      GetCurrentTimeAsDuration().IsNull()) {
    // If |previous play state| is idle or paused, or the current time is
    // unresolved, we apply any pending playback rate on animation immediately.
    ApplyPendingPlaybackRate();

    // We don't need to update timing or post an update here because:
    //
    // * the current time hasn't changed -- it's either unresolved or fixed
    //   with a hold time -- so the output won't have changed
    // * the finished state won't have changed even if the sign of the
    //   playback rate changed since we're not finished (we're paused or idle)
    // * the playback rate on layers doesn't need to be updated since we're not
    //   moving. Once we get a start time etc. we'll update the playback rate
    //   then.
    //
    // However we still need to update the relevance and effect set as well as
    // notifying observers.
    UpdateEffect(PostRestyleMode::Never);
    if (IsRelevant()) {
      MutationObservers::NotifyAnimationChanged(this);
    }
  } else if (playState == AnimationPlayState::Finished) {
    MOZ_ASSERT(mTimeline && !mTimeline->GetCurrentTimeAsDuration().IsNull(),
               "If we have no active timeline, we should be idle or paused");
    if (aPlaybackRate != 0) {
      // The unconstrained current time can only be unresolved if either we
      // don't have an active timeline (and we already asserted that is not
      // true) or we have an unresolved start time (in which case we should be
      // paused).
      MOZ_ASSERT(!GetUnconstrainedCurrentTime().IsNull(),
                 "Unconstrained current time should be resolved");
      TimeDuration unconstrainedCurrentTime =
          GetUnconstrainedCurrentTime().Value();
      TimeDuration timelineTime = mTimeline->GetCurrentTimeAsDuration().Value();
      mStartTime = StartTimeFromTimelineTime(
          timelineTime, unconstrainedCurrentTime, aPlaybackRate);
    } else {
      mStartTime = mTimeline->GetCurrentTimeAsDuration();
    }

    ApplyPendingPlaybackRate();

    // Even though we preserve the current time, we might now leave the finished
    // state (e.g. if the playback rate changes sign) so we need to update
    // timing.
    UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);
    if (IsRelevant()) {
      MutationObservers::NotifyAnimationChanged(this);
    }
    PostUpdate();
  } else {
    ErrorResult rv;
    Play(rv, LimitBehavior::Continue);
    MOZ_ASSERT(!rv.Failed(),
               "We should only fail to play when using auto-rewind behavior");
  }
}

// https://drafts.csswg.org/web-animations/#play-state
AnimationPlayState Animation::PlayState() const {
  Nullable<TimeDuration> currentTime = GetCurrentTimeAsDuration();
  if (currentTime.IsNull() && mStartTime.IsNull() && !Pending()) {
    return AnimationPlayState::Idle;
  }

  if (mPendingState == PendingState::PausePending ||
      (mStartTime.IsNull() && !Pending())) {
    return AnimationPlayState::Paused;
  }

  double playbackRate = CurrentOrPendingPlaybackRate();
  if (!currentTime.IsNull() &&
      ((playbackRate > 0.0 && currentTime.Value() >= EffectEnd()) ||
       (playbackRate < 0.0 && currentTime.Value() <= TimeDuration()))) {
    return AnimationPlayState::Finished;
  }

  return AnimationPlayState::Running;
}

Promise* Animation::GetReady(ErrorResult& aRv) {
  nsCOMPtr<nsIGlobalObject> global = GetOwnerGlobal();
  if (!mReady && global) {
    mReady = Promise::Create(global, aRv);  // Lazily create on demand
  }
  if (!mReady) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }
  if (!Pending()) {
    mReady->MaybeResolve(this);
  }
  return mReady;
}

Promise* Animation::GetFinished(ErrorResult& aRv) {
  nsCOMPtr<nsIGlobalObject> global = GetOwnerGlobal();
  if (!mFinished && global) {
    mFinished = Promise::Create(global, aRv);  // Lazily create on demand
  }
  if (!mFinished) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }
  if (mFinishedIsResolved) {
    MaybeResolveFinishedPromise();
  }
  return mFinished;
}

// https://drafts.csswg.org/web-animations/#cancel-an-animation
void Animation::Cancel(PostRestyleMode aPostRestyle) {
  bool newlyIdle = false;

  if (PlayState() != AnimationPlayState::Idle) {
    newlyIdle = true;

    ResetPendingTasks();

    if (mFinished) {
      mFinished->MaybeReject(NS_ERROR_DOM_ABORT_ERR);
      // mFinished can already be resolved.
      MOZ_ALWAYS_TRUE(mFinished->SetAnyPromiseIsHandled());
    }
    ResetFinishedPromise();

    QueuePlaybackEvent(nsGkAtoms::oncancel,
                       GetTimelineCurrentTimeAsTimeStamp());
  }

  StickyTimeDuration activeTime =
      mEffect ? mEffect->GetComputedTiming().mActiveTime : StickyTimeDuration();

  mHoldTime.SetNull();
  mStartTime.SetNull();

  // Allow our effect to remove itself from the its target element's EffectSet.
  UpdateEffect(aPostRestyle);

  if (mTimeline) {
    mTimeline->RemoveAnimation(this);
  }
  MaybeQueueCancelEvent(activeTime);

  if (newlyIdle && aPostRestyle == PostRestyleMode::IfNeeded) {
    PostUpdate();
  }
}

// https://drafts.csswg.org/web-animations/#finish-an-animation
void Animation::Finish(ErrorResult& aRv) {
  double effectivePlaybackRate = CurrentOrPendingPlaybackRate();

  if (effectivePlaybackRate == 0) {
    return aRv.ThrowInvalidStateError(
        "Can't finish animation with zero playback rate");
  }
  if (effectivePlaybackRate > 0 && EffectEnd() == TimeDuration::Forever()) {
    return aRv.ThrowInvalidStateError("Can't finish infinite animation");
  }

  AutoMutationBatchForAnimation mb(*this);

  ApplyPendingPlaybackRate();

  // Seek to the end
  TimeDuration limit =
      mPlaybackRate > 0 ? TimeDuration(EffectEnd()) : TimeDuration(0);
  bool didChange = GetCurrentTimeAsDuration() != Nullable<TimeDuration>(limit);
  SilentlySetCurrentTime(limit);

  // If we are paused or play-pending we need to fill in the start time in
  // order to transition to the finished state.
  //
  // We only do this, however, if we have an active timeline. If we have an
  // inactive timeline we can't transition into the finished state just like
  // we can't transition to the running state (this finished state is really
  // a substate of the running state).
  if (mStartTime.IsNull() && mTimeline &&
      !mTimeline->GetCurrentTimeAsDuration().IsNull()) {
    mStartTime = StartTimeFromTimelineTime(
        mTimeline->GetCurrentTimeAsDuration().Value(), limit, mPlaybackRate);
    didChange = true;
  }

  // If we just resolved the start time for a pause or play-pending
  // animation, we need to clear the task. We don't do this as a branch of
  // the above however since we can have a play-pending animation with a
  // resolved start time if we aborted a pause operation.
  if (!mStartTime.IsNull() && (mPendingState == PendingState::PlayPending ||
                               mPendingState == PendingState::PausePending)) {
    if (mPendingState == PendingState::PausePending) {
      mHoldTime.SetNull();
    }
    CancelPendingTasks();
    didChange = true;
    if (mReady) {
      mReady->MaybeResolve(this);
    }
  }
  UpdateTiming(SeekFlag::DidSeek, SyncNotifyFlag::Sync);
  if (didChange && IsRelevant()) {
    MutationObservers::NotifyAnimationChanged(this);
  }
  PostUpdate();
}

void Animation::Play(ErrorResult& aRv, LimitBehavior aLimitBehavior) {
  PlayNoUpdate(aRv, aLimitBehavior);
  PostUpdate();
}

// https://drafts.csswg.org/web-animations/#reverse-an-animation
void Animation::Reverse(ErrorResult& aRv) {
  if (!mTimeline) {
    return aRv.ThrowInvalidStateError(
        "Can't reverse an animation with no associated timeline");
  }
  if (mTimeline->GetCurrentTimeAsDuration().IsNull()) {
    return aRv.ThrowInvalidStateError(
        "Can't reverse an animation associated with an inactive timeline");
  }

  double effectivePlaybackRate = CurrentOrPendingPlaybackRate();

  if (effectivePlaybackRate == 0.0) {
    return;
  }

  Maybe<double> originalPendingPlaybackRate = mPendingPlaybackRate;

  mPendingPlaybackRate = Some(-effectivePlaybackRate);

  Play(aRv, LimitBehavior::AutoRewind);

  // If Play() threw, restore state and don't report anything to mutation
  // observers.
  if (aRv.Failed()) {
    mPendingPlaybackRate = originalPendingPlaybackRate;
  }

  // Play(), above, unconditionally calls PostUpdate so we don't need to do
  // it here.
}

void Animation::Persist() {
  if (mReplaceState == AnimationReplaceState::Persisted) {
    return;
  }

  bool wasRemoved = mReplaceState == AnimationReplaceState::Removed;

  mReplaceState = AnimationReplaceState::Persisted;

  // If the animation is not (yet) removed, there should be no side effects of
  // persisting it.
  if (wasRemoved) {
    UpdateEffect(PostRestyleMode::IfNeeded);
    PostUpdate();
  }
}

DocGroup* Animation::GetDocGroup() {
  Document* doc = GetRenderedDocument();
  return doc ? doc->GetDocGroup() : nullptr;
}

// https://drafts.csswg.org/web-animations/#dom-animation-commitstyles
void Animation::CommitStyles(ErrorResult& aRv) {
  if (!mEffect) {
    return;
  }

  // Take an owning reference to the keyframe effect. This will ensure that
  // this Animation and the target element remain alive after flushing style.
  RefPtr<KeyframeEffect> keyframeEffect = mEffect->AsKeyframeEffect();
  if (!keyframeEffect) {
    return;
  }

  NonOwningAnimationTarget target = keyframeEffect->GetAnimationTarget();
  if (!target) {
    return;
  }

  if (target.mPseudoType != PseudoStyleType::NotPseudo) {
    return aRv.ThrowNoModificationAllowedError(
        "Can't commit styles of a pseudo-element");
  }

  // Check it is an element with a style attribute
  RefPtr<nsStyledElement> styledElement =
      nsStyledElement::FromNodeOrNull(target.mElement);
  if (!styledElement) {
    return aRv.ThrowNoModificationAllowedError(
        "Target is not capable of having a style attribute");
  }

  // Hold onto a strong reference to the doc in case the flush destroys it.
  RefPtr<Document> doc = target.mElement->GetComposedDoc();

  // Flush frames before checking if the target element is rendered since the
  // result could depend on pending style changes, and IsRendered() looks at the
  // primary frame.
  if (doc) {
    doc->FlushPendingNotifications(FlushType::Frames);
  }
  if (!target.mElement->IsRendered()) {
    return aRv.ThrowInvalidStateError("Target is not rendered");
  }
  nsPresContext* presContext =
      nsContentUtils::GetContextForContent(target.mElement);
  if (!presContext) {
    return aRv.ThrowInvalidStateError("Target is not rendered");
  }

  // Get the computed animation values
  UniquePtr<StyleAnimationValueMap> animationValues(
      Servo_AnimationValueMap_Create());
  if (!presContext->EffectCompositor()->ComposeServoAnimationRuleForEffect(
          *keyframeEffect, CascadeLevel(), animationValues.get())) {
    NS_WARNING("Failed to compose animation style to commit");
    return;
  }

  // Calling SetCSSDeclaration will trigger attribute setting code.
  // Start the update now so that the old rule doesn't get used
  // between when we mutate the declaration and when we set the new
  // rule.
  mozAutoDocUpdate autoUpdate(target.mElement->OwnerDoc(), true);

  // Get the inline style to append to
  RefPtr<DeclarationBlock> declarationBlock;
  if (auto* existing = target.mElement->GetInlineStyleDeclaration()) {
    declarationBlock = existing->EnsureMutable();
  } else {
    declarationBlock = new DeclarationBlock();
    declarationBlock->SetDirty();
  }

  // Prepare the callback
  MutationClosureData closureData;
  closureData.mShouldBeCalled = true;
  closureData.mElement = target.mElement;
  DeclarationBlockMutationClosure beforeChangeClosure = {
      nsDOMCSSAttributeDeclaration::MutationClosureFunction,
      &closureData,
  };

  // Set the animated styles
  bool changed = false;
  const AnimatedPropertyIDSet& properties = keyframeEffect->GetPropertySet();
  for (const AnimatedPropertyID& property : properties) {
    RefPtr<StyleAnimationValue> computedValue =
        Servo_AnimationValueMap_GetValue(animationValues.get(), &property)
            .Consume();
    if (computedValue) {
      changed |= Servo_DeclarationBlock_SetPropertyToAnimationValue(
          declarationBlock->Raw(), computedValue, beforeChangeClosure);
    }
  }

  if (!changed) {
    MOZ_ASSERT(!closureData.mWasCalled);
    return;
  }

  MOZ_ASSERT(closureData.mWasCalled);
  // Update inline style declaration
  target.mElement->SetInlineStyleDeclaration(*declarationBlock, closureData);
}

// ---------------------------------------------------------------------------
//
// JS wrappers for Animation interface:
//
// ---------------------------------------------------------------------------

Nullable<double> Animation::GetStartTimeAsDouble() const {
  return AnimationUtils::TimeDurationToDouble(mStartTime, mRTPCallerType);
}

void Animation::SetStartTimeAsDouble(const Nullable<double>& aStartTime) {
  return SetStartTime(AnimationUtils::DoubleToTimeDuration(aStartTime));
}

Nullable<double> Animation::GetCurrentTimeAsDouble() const {
  return AnimationUtils::TimeDurationToDouble(GetCurrentTimeAsDuration(),
                                              mRTPCallerType);
}

void Animation::SetCurrentTimeAsDouble(const Nullable<double>& aCurrentTime,
                                       ErrorResult& aRv) {
  if (aCurrentTime.IsNull()) {
    if (!GetCurrentTimeAsDuration().IsNull()) {
      aRv.ThrowTypeError(
          "Current time is resolved but trying to set it to an unresolved "
          "time");
    }
    return;
  }

  return SetCurrentTime(TimeDuration::FromMilliseconds(aCurrentTime.Value()));
}

// ---------------------------------------------------------------------------

void Animation::Tick(AnimationTimeline::TickState& aTickState) {
  if (Pending()) {
    if (!mPendingReadyTime.IsNull()) {
      TryTriggerNow();
    } else if (MOZ_LIKELY(mTimeline)) {
      // Makes sure that we trigger the animation on the next tick but,
      // importantly, with this tick's timestamp.
      mPendingReadyTime = mTimeline->GetCurrentTimeAsTimeStamp();
    }
  }

  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Sync);

  // Check for changes to whether or not this animation is replaceable.
  bool isReplaceable = IsReplaceable();
  if (isReplaceable && !mWasReplaceableAtLastTick) {
    ScheduleReplacementCheck();
  }
  mWasReplaceableAtLastTick = isReplaceable;

  if (!mEffect) {
    return;
  }

  // Update layers if we are newly finished.
  KeyframeEffect* keyframeEffect = mEffect->AsKeyframeEffect();
  if (keyframeEffect && !keyframeEffect->Properties().IsEmpty() &&
      !mFinishedAtLastComposeStyle &&
      PlayState() == AnimationPlayState::Finished) {
    PostUpdate();
  }
}

bool Animation::TryTriggerNow() {
  if (!Pending()) {
    return true;
  }
  // If we don't have an active timeline we can't trigger the animation.
  if (NS_WARN_IF(!mTimeline)) {
    return false;
  }
  auto currentTime = mPendingReadyTime.IsNull()
                         ? mTimeline->GetCurrentTimeAsDuration()
                         : mTimeline->ToTimelineTime(mPendingReadyTime);
  mPendingReadyTime = {};
  if (NS_WARN_IF(currentTime.IsNull())) {
    return false;
  }
  FinishPendingAt(currentTime.Value());
  return true;
}

TimeStamp Animation::AnimationTimeToTimeStamp(
    const StickyTimeDuration& aTime) const {
  // Initializes to null. Return the same object every time to benefit from
  // return-value-optimization.
  TimeStamp result;

  // We *don't* check for mTimeline->TracksWallclockTime() here because that
  // method only tells us if the timeline times can be converted to
  // TimeStamps that can be compared to TimeStamp::Now() or not, *not*
  // whether the timelines can be converted to TimeStamp values at all.
  //
  // Furthermore, we want to be able to use this method when the refresh driver
  // is under test control (in which case TracksWallclockTime() will return
  // false).
  //
  // Once we introduce timelines that are not time-based we will need to
  // differentiate between them here and determine how to sort their events.
  if (!mTimeline) {
    return result;
  }

  // Check the time is convertible to a timestamp
  if (aTime == TimeDuration::Forever() || mPlaybackRate == 0.0 ||
      mStartTime.IsNull()) {
    return result;
  }

  // Invert the standard relation:
  //   current time = (timeline time - start time) * playback rate
  TimeDuration timelineTime =
      TimeDuration(aTime).MultDouble(1.0 / mPlaybackRate) + mStartTime.Value();

  result = mTimeline->ToTimeStamp(timelineTime);
  return result;
}

TimeStamp Animation::ElapsedTimeToTimeStamp(
    const StickyTimeDuration& aElapsedTime) const {
  TimeDuration delay =
      mEffect ? mEffect->NormalizedTiming().Delay() : TimeDuration();
  return AnimationTimeToTimeStamp(aElapsedTime + delay);
}

// https://drafts.csswg.org/web-animations/#silently-set-the-current-time
void Animation::SilentlySetCurrentTime(const TimeDuration& aSeekTime) {
  // TODO: Bug 1762238: Introduce "valid seek time" after introducing
  // CSSNumberish time values.
  // https://drafts.csswg.org/web-animations-2/#silently-set-the-current-time

  if (!mHoldTime.IsNull() || mStartTime.IsNull() || !mTimeline ||
      mTimeline->GetCurrentTimeAsDuration().IsNull() || mPlaybackRate == 0.0) {
    mHoldTime.SetValue(aSeekTime);
  } else {
    mStartTime =
        StartTimeFromTimelineTime(mTimeline->GetCurrentTimeAsDuration().Value(),
                                  aSeekTime, mPlaybackRate);
  }

  if (!mTimeline || mTimeline->GetCurrentTimeAsDuration().IsNull()) {
    mStartTime.SetNull();
  }

  mPreviousCurrentTime.SetNull();
  mResetCurrentTimeOnResume = false;
}

bool Animation::ShouldBeSynchronizedWithMainThread(
    const nsCSSPropertyIDSet& aPropertySet, const nsIFrame* aFrame,
    AnimationPerformanceWarning::Type& aPerformanceWarning) const {
  // Only synchronize playing animations
  if (!IsPlaying()) {
    return false;
  }

  // Currently only transform animations need to be synchronized
  if (!aPropertySet.Intersects(nsCSSPropertyIDSet::TransformLikeProperties())) {
    return false;
  }

  KeyframeEffect* keyframeEffect =
      mEffect ? mEffect->AsKeyframeEffect() : nullptr;
  if (!keyframeEffect) {
    return false;
  }

  return keyframeEffect->ShouldBlockAsyncTransformAnimations(
      aFrame, aPropertySet, aPerformanceWarning);
}

void Animation::UpdateRelevance() {
  bool wasRelevant = mIsRelevant;
  mIsRelevant = mReplaceState != AnimationReplaceState::Removed &&
                (HasCurrentEffect() || IsInEffect());

  // Notify animation observers.
  if (wasRelevant && !mIsRelevant) {
    MutationObservers::NotifyAnimationRemoved(this);
  } else if (!wasRelevant && mIsRelevant) {
    UpdateHiddenByContentVisibility();
    MutationObservers::NotifyAnimationAdded(this);
  }
}

template <class T>
bool IsMarkupAnimation(T* aAnimation) {
  return aAnimation && aAnimation->IsTiedToMarkup();
}

// https://drafts.csswg.org/web-animations/#replaceable-animation
bool Animation::IsReplaceable() const {
  // We never replace CSS animations or CSS transitions since they are managed
  // by CSS.
  if (IsMarkupAnimation(AsCSSAnimation()) ||
      IsMarkupAnimation(AsCSSTransition())) {
    return false;
  }

  // Only finished animations can be replaced.
  if (PlayState() != AnimationPlayState::Finished) {
    return false;
  }

  // Already removed animations cannot be replaced.
  if (ReplaceState() == AnimationReplaceState::Removed) {
    return false;
  }

  // We can only replace an animation if we know that, uninterfered, it would
  // never start playing again. That excludes any animations on timelines that
  // aren't monotonically increasing.
  //
  // If we don't have any timeline at all, then we can't be in the finished
  // state (since we need both a resolved start time and current time for that)
  // and will have already returned false above.
  //
  // (However, if it ever does become possible to be finished without a timeline
  // then we will want to return false here since it probably suggests an
  // animation being driven directly by script, in which case we can't assume
  // anything about how they will behave.)
  if (!GetTimeline() || !GetTimeline()->TracksWallclockTime()) {
    return false;
  }

  // If the animation doesn't have an effect then we can't determine if it is
  // filling or not so just leave it alone.
  if (!GetEffect()) {
    return false;
  }

  // At the time of writing we only know about KeyframeEffects. If we introduce
  // other types of effects we will need to decide if they are replaceable or
  // not.
  MOZ_ASSERT(GetEffect()->AsKeyframeEffect(),
             "Effect should be a keyframe effect");

  // We only replace animations that are filling.
  if (GetEffect()->GetComputedTiming().mProgress.IsNull()) {
    return false;
  }

  // We should only replace animations with a target element (since otherwise
  // what other effects would we consider when determining if they are covered
  // or not?).
  if (!GetEffect()->AsKeyframeEffect()->GetAnimationTarget()) {
    return false;
  }

  return true;
}

bool Animation::IsRemovable() const {
  return ReplaceState() == AnimationReplaceState::Active && IsReplaceable();
}

void Animation::ScheduleReplacementCheck() {
  MOZ_ASSERT(
      IsReplaceable(),
      "Should only schedule a replacement check for a replaceable animation");

  // If IsReplaceable() is true, the following should also hold
  MOZ_ASSERT(GetEffect());
  MOZ_ASSERT(GetEffect()->AsKeyframeEffect());

  NonOwningAnimationTarget target =
      GetEffect()->AsKeyframeEffect()->GetAnimationTarget();

  MOZ_ASSERT(target);

  nsPresContext* presContext =
      nsContentUtils::GetContextForContent(target.mElement);
  if (presContext) {
    presContext->EffectCompositor()->NoteElementForReducing(target);
  }
}

void Animation::MaybeScheduleReplacementCheck() {
  if (!IsReplaceable()) {
    return;
  }

  ScheduleReplacementCheck();
}

void Animation::Remove() {
  MOZ_ASSERT(IsRemovable(),
             "Should not be trying to remove an effect that is not removable");

  mReplaceState = AnimationReplaceState::Removed;

  UpdateEffect(PostRestyleMode::IfNeeded);
  PostUpdate();

  QueuePlaybackEvent(nsGkAtoms::onremove, GetTimelineCurrentTimeAsTimeStamp());
}

bool Animation::HasLowerCompositeOrderThan(const Animation& aOther) const {
  // 0. Object-equality case
  if (&aOther == this) {
    return false;
  }

  // 1. CSS Transitions sort lowest
  {
    auto asCSSTransitionForSorting =
        [](const Animation& anim) -> const CSSTransition* {
      const CSSTransition* transition = anim.AsCSSTransition();
      return transition && transition->IsTiedToMarkup() ? transition : nullptr;
    };
    auto thisTransition = asCSSTransitionForSorting(*this);
    auto otherTransition = asCSSTransitionForSorting(aOther);
    if (thisTransition && otherTransition) {
      return thisTransition->HasLowerCompositeOrderThan(*otherTransition);
    }
    if (thisTransition || otherTransition) {
      // Cancelled transitions no longer have an owning element. To be strictly
      // correct we should store a strong reference to the owning element
      // so that if we arrive here while sorting cancel events, we can sort
      // them in the correct order.
      //
      // However, given that cancel events are almost always queued
      // synchronously in some deterministic manner, we can be fairly sure
      // that cancel events will be dispatched in a deterministic order
      // (which is our only hard requirement until specs say otherwise).
      // Furthermore, we only reach here when we have events with equal
      // timestamps so this is an edge case we can probably ignore for now.
      return thisTransition;
    }
  }

  // 2. CSS Animations sort next
  {
    auto asCSSAnimationForSorting =
        [](const Animation& anim) -> const CSSAnimation* {
      const CSSAnimation* animation = anim.AsCSSAnimation();
      return animation && animation->IsTiedToMarkup() ? animation : nullptr;
    };
    auto thisAnimation = asCSSAnimationForSorting(*this);
    auto otherAnimation = asCSSAnimationForSorting(aOther);
    if (thisAnimation && otherAnimation) {
      return thisAnimation->HasLowerCompositeOrderThan(*otherAnimation);
    }
    if (thisAnimation || otherAnimation) {
      return thisAnimation;
    }
  }

  // Subclasses of Animation repurpose mAnimationIndex to implement their
  // own brand of composite ordering. However, by this point we should have
  // handled any such custom composite ordering so we should now have unique
  // animation indices.
  MOZ_ASSERT(mAnimationIndex != aOther.mAnimationIndex,
             "Animation indices should be unique");

  // 3. Finally, generic animations sort by their position in the global
  // animation array.
  return mAnimationIndex < aOther.mAnimationIndex;
}

void Animation::WillComposeStyle() {
  mFinishedAtLastComposeStyle = (PlayState() == AnimationPlayState::Finished);

  MOZ_ASSERT(mEffect);

  KeyframeEffect* keyframeEffect = mEffect->AsKeyframeEffect();
  if (keyframeEffect) {
    keyframeEffect->WillComposeStyle();
  }
}

void Animation::ComposeStyle(
    StyleAnimationValueMap& aComposeResult,
    const InvertibleAnimatedPropertyIDSet& aPropertiesToSkip) {
  if (!mEffect) {
    return;
  }

  // In order to prevent flicker, there are a few cases where we want to use
  // a different time for rendering that would otherwise be returned by
  // GetCurrentTimeAsDuration. These are:
  //
  // (a) For animations that are pausing but which are still running on the
  //     compositor. In this case we send a layer transaction that removes the
  //     animation but which also contains the animation values calculated on
  //     the main thread. To prevent flicker when this occurs we want to ensure
  //     the timeline time used to calculate the main thread animation values
  //     does not lag far behind the time used on the compositor. Ideally we
  //     would like to use the "animation ready time", but for now we just use
  //     the current wallclock time. TODO(emilio): After bug 1864425 it seems we
  //     could just use the ready time, or maybe we can remove this?
  //
  // (b) For animations that are pausing that we have already taken off the
  //     compositor. In this case we record a pending ready time but we don't
  //     apply it until the next tick. However, while waiting for the next tick,
  //     we should still use the pending ready time as the timeline time. If we
  //     use the regular timeline time the animation may appear jump backwards
  //     if the main thread's timeline time lags behind the compositor.
  //
  // (c) For animations that are play-pending due to an aborted pause operation
  //     (i.e. a pause operation that was interrupted before we entered the
  //     paused state). When we cancel a pending pause we might momentarily take
  //     the animation off the compositor, only to re-add it moments later. In
  //     that case the compositor might have been ahead of the main thread so we
  //     should use the current wallclock time to ensure the animation doesn't
  //     temporarily jump backwards.
  //
  // To address each of these cases we temporarily tweak the hold time
  // immediately before updating the style rule and then restore it immediately
  // afterwards. This is purely to prevent visual flicker. Other behavior
  // such as dispatching events continues to rely on the regular timeline time.
  const bool pending = Pending();
  {
    AutoRestore<Nullable<TimeDuration>> restoreHoldTime(mHoldTime);
    if (pending && mHoldTime.IsNull() && !mStartTime.IsNull()) {
      Nullable<TimeDuration> timeToUse;
      if (mTimeline && mTimeline->TracksWallclockTime()) {
        timeToUse = mTimeline->ToTimelineTime(TimeStamp::Now());
      }
      if (!timeToUse.IsNull()) {
        mHoldTime = CurrentTimeFromTimelineTime(
            timeToUse.Value(), mStartTime.Value(), mPlaybackRate);
      }
    }

    KeyframeEffect* keyframeEffect = mEffect->AsKeyframeEffect();
    if (keyframeEffect) {
      keyframeEffect->ComposeStyle(aComposeResult, aPropertiesToSkip);
    }
  }

  MOZ_ASSERT(
      pending == Pending(),
      "Pending state should not change during the course of compositing");
}

void Animation::NotifyEffectTimingUpdated() {
  MOZ_ASSERT(mEffect,
             "We should only update effect timing when we have a target "
             "effect");
  UpdateTiming(Animation::SeekFlag::NoSeek, Animation::SyncNotifyFlag::Async);
}

void Animation::NotifyEffectPropertiesUpdated() {
  MOZ_ASSERT(mEffect,
             "We should only update effect properties when we have a target "
             "effect");

  MaybeScheduleReplacementCheck();
}

void Animation::NotifyEffectTargetUpdated() {
  MOZ_ASSERT(mEffect,
             "We should only update the effect target when we have a target "
             "effect");

  MaybeScheduleReplacementCheck();
}

static TimeStamp EnsurePaintIsScheduled(Document& aDoc) {
  PresShell* presShell = aDoc.GetPresShell();
  if (!presShell) {
    return {};
  }
  nsIFrame* rootFrame = presShell->GetRootFrame();
  if (!rootFrame) {
    return {};
  }
  rootFrame->SchedulePaintWithoutInvalidatingObservers();
  auto* rd = rootFrame->PresContext()->RefreshDriver();
  if (!rd->IsInRefresh()) {
    return {};
  }
  return rd->MostRecentRefresh(/* aEnsureTimerStarted = */ false);
}

// https://drafts.csswg.org/web-animations/#play-an-animation
void Animation::PlayNoUpdate(ErrorResult& aRv, LimitBehavior aLimitBehavior) {
  AutoMutationBatchForAnimation mb(*this);

  const bool isAutoRewind = aLimitBehavior == LimitBehavior::AutoRewind;
  const bool abortedPause = mPendingState == PendingState::PausePending;
  double effectivePlaybackRate = CurrentOrPendingPlaybackRate();

  Nullable<TimeDuration> currentTime = GetCurrentTimeAsDuration();
  if (mResetCurrentTimeOnResume) {
    currentTime.SetNull();
    mResetCurrentTimeOnResume = false;
  }

  Nullable<TimeDuration> seekTime;
  if (isAutoRewind) {
    if (effectivePlaybackRate >= 0.0 &&
        (currentTime.IsNull() || currentTime.Value() < TimeDuration() ||
         currentTime.Value() >= EffectEnd())) {
      seekTime.SetValue(TimeDuration());
    } else if (effectivePlaybackRate < 0.0 &&
               (currentTime.IsNull() || currentTime.Value() <= TimeDuration() ||
                currentTime.Value() > EffectEnd())) {
      if (EffectEnd() == TimeDuration::Forever()) {
        return aRv.ThrowInvalidStateError(
            "Can't rewind animation with infinite effect end");
      }
      seekTime.SetValue(TimeDuration(EffectEnd()));
    }
  }

  if (seekTime.IsNull() && mStartTime.IsNull() && currentTime.IsNull()) {
    seekTime.SetValue(TimeDuration());
  }

  if (!seekTime.IsNull()) {
    if (HasFiniteTimeline()) {
      mStartTime = seekTime;
      mHoldTime.SetNull();
      ApplyPendingPlaybackRate();
    } else {
      mHoldTime = seekTime;
    }
  }

  bool reuseReadyPromise = false;
  if (mPendingState != PendingState::NotPending) {
    CancelPendingTasks();
    reuseReadyPromise = true;
  }

  // If the hold time is null then we're already playing normally and,
  // typically, we can bail out here.
  //
  // However, there are two cases where we can't do that:
  //
  // (a) If we just aborted a pause. In this case, for consistency, we need to
  //     go through the motions of doing an asynchronous start.
  //
  // (b) If we have timing changes (specifically a change to the playbackRate)
  //     that should be applied asynchronously.
  //
  if (mHoldTime.IsNull() && seekTime.IsNull() && !abortedPause &&
      !mPendingPlaybackRate) {
    return;
  }

  // Clear the start time until we resolve a new one. We do this except
  // for the case where we are aborting a pause and don't have a hold time.
  //
  // If we're aborting a pause and *do* have a hold time (e.g. because
  // the animation is finished or we just applied the auto-rewind behavior
  // above) we should respect it by clearing the start time. If we *don't*
  // have a hold time we should keep the current start time so that the
  // the animation continues moving uninterrupted by the aborted pause.
  //
  // (If we're not aborting a pause, mHoldTime must be resolved by now
  //  or else we would have returned above.)
  if (!mHoldTime.IsNull()) {
    mStartTime.SetNull();
  }

  if (!reuseReadyPromise) {
    // Clear ready promise. We'll create a new one lazily.
    mReady = nullptr;
  }

  mPendingState = PendingState::PlayPending;
  mPendingReadyTime = {};
  if (Document* doc = GetRenderedDocument()) {
    if (HasFiniteTimeline()) {
      // Always schedule a task even if we would like to let this animation
      // immediately ready, per spec.
      // https://drafts.csswg.org/web-animations/#playing-an-animation-section
      // If there's no rendered document, we fail to track this animation, so
      // let the scroll frame to trigger it when ticking.
      doc->GetOrCreateScrollTimelineAnimationTracker()->AddPending(*this);
    }
    // Make sure to try to schedule a tick.
    mPendingReadyTime = EnsurePaintIsScheduled(*doc);
  }

  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);
  if (IsRelevant()) {
    MutationObservers::NotifyAnimationChanged(this);
  }
}

// https://drafts.csswg.org/web-animations/#pause-an-animation
void Animation::Pause(ErrorResult& aRv) {
  if (IsPausedOrPausing()) {
    return;
  }

  AutoMutationBatchForAnimation mb(*this);

  Nullable<TimeDuration> seekTime;
  // If we are transitioning from idle, fill in the current time
  if (GetCurrentTimeAsDuration().IsNull()) {
    if (mPlaybackRate >= 0.0) {
      seekTime.SetValue(TimeDuration(0));
    } else {
      if (EffectEnd() == TimeDuration::Forever()) {
        return aRv.ThrowInvalidStateError("Can't seek to infinite effect end");
      }
      seekTime.SetValue(TimeDuration(EffectEnd()));
    }
  }

  if (!seekTime.IsNull()) {
    if (HasFiniteTimeline()) {
      mStartTime = seekTime;
    } else {
      mHoldTime = seekTime;
    }
  }

  bool reuseReadyPromise = false;
  if (mPendingState == PendingState::PlayPending) {
    CancelPendingTasks();
    reuseReadyPromise = true;
  }

  if (!reuseReadyPromise) {
    // Clear ready promise. We'll create a new one lazily.
    mReady = nullptr;
  }

  mPendingState = PendingState::PausePending;
  mPendingReadyTime = {};
  // See the relevant PlayPending code for comments.
  if (Document* doc = GetRenderedDocument()) {
    if (HasFiniteTimeline()) {
      doc->GetOrCreateScrollTimelineAnimationTracker()->AddPending(*this);
    }
    mPendingReadyTime = EnsurePaintIsScheduled(*doc);
  }

  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);
  if (IsRelevant()) {
    MutationObservers::NotifyAnimationChanged(this);
  }

  PostUpdate();
}

// https://drafts.csswg.org/web-animations/#play-an-animation
void Animation::ResumeAt(const TimeDuration& aReadyTime) {
  // This method is only expected to be called for an animation that is
  // waiting to play. We can easily adapt it to handle other states
  // but it's currently not necessary.
  MOZ_ASSERT(mPendingState == PendingState::PlayPending,
             "Expected to resume a play-pending animation");
  MOZ_ASSERT(!mHoldTime.IsNull() || !mStartTime.IsNull(),
             "An animation in the play-pending state should have either a"
             " resolved hold time or resolved start time");

  AutoMutationBatchForAnimation mb(*this);
  bool hadPendingPlaybackRate = mPendingPlaybackRate.isSome();

  if (!mHoldTime.IsNull()) {
    // The hold time is set, so we don't need any special handling to preserve
    // the current time.
    ApplyPendingPlaybackRate();
    mStartTime =
        StartTimeFromTimelineTime(aReadyTime, mHoldTime.Value(), mPlaybackRate);
    if (mPlaybackRate != 0) {
      mHoldTime.SetNull();
    }
  } else if (!mStartTime.IsNull() && mPendingPlaybackRate) {
    // Apply any pending playback rate, preserving the current time.
    TimeDuration currentTimeToMatch = CurrentTimeFromTimelineTime(
        aReadyTime, mStartTime.Value(), mPlaybackRate);
    ApplyPendingPlaybackRate();
    mStartTime = StartTimeFromTimelineTime(aReadyTime, currentTimeToMatch,
                                           mPlaybackRate);
    if (mPlaybackRate == 0) {
      mHoldTime.SetValue(currentTimeToMatch);
    }
  }

  mPendingState = PendingState::NotPending;

  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Sync);

  // If we had a pending playback rate, we will have now applied it so we need
  // to notify observers.
  if (hadPendingPlaybackRate && IsRelevant()) {
    MutationObservers::NotifyAnimationChanged(this);
  }

  if (mReady) {
    mReady->MaybeResolve(this);
  }
}

void Animation::PauseAt(const TimeDuration& aReadyTime) {
  MOZ_ASSERT(mPendingState == PendingState::PausePending,
             "Expected to pause a pause-pending animation");

  if (!mStartTime.IsNull() && mHoldTime.IsNull()) {
    mHoldTime = CurrentTimeFromTimelineTime(aReadyTime, mStartTime.Value(),
                                            mPlaybackRate);
  }
  ApplyPendingPlaybackRate();
  mStartTime.SetNull();
  mPendingState = PendingState::NotPending;

  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);

  if (mReady) {
    mReady->MaybeResolve(this);
  }
}

void Animation::UpdateTiming(SeekFlag aSeekFlag,
                             SyncNotifyFlag aSyncNotifyFlag) {
  // We call UpdateFinishedState before UpdateEffect because the former
  // can change the current time, which is used by the latter.
  UpdateFinishedState(aSeekFlag, aSyncNotifyFlag);
  UpdateEffect(PostRestyleMode::IfNeeded);

  if (mTimeline) {
    mTimeline->NotifyAnimationUpdated(*this);
  }
}

// https://drafts.csswg.org/web-animations/#update-an-animations-finished-state
void Animation::UpdateFinishedState(SeekFlag aSeekFlag,
                                    SyncNotifyFlag aSyncNotifyFlag) {
  Nullable<TimeDuration> unconstrainedCurrentTime =
      aSeekFlag == SeekFlag::NoSeek ? GetUnconstrainedCurrentTime()
                                    : GetCurrentTimeAsDuration();
  TimeDuration effectEnd = TimeDuration(EffectEnd());

  if (!unconstrainedCurrentTime.IsNull() && !mStartTime.IsNull() &&
      mPendingState == PendingState::NotPending) {
    if (mPlaybackRate > 0.0 && unconstrainedCurrentTime.Value() >= effectEnd) {
      if (aSeekFlag == SeekFlag::DidSeek) {
        mHoldTime = unconstrainedCurrentTime;
      } else if (!mPreviousCurrentTime.IsNull()) {
        mHoldTime.SetValue(std::max(mPreviousCurrentTime.Value(), effectEnd));
      } else {
        mHoldTime.SetValue(effectEnd);
      }
    } else if (mPlaybackRate < 0.0 &&
               unconstrainedCurrentTime.Value() <= TimeDuration()) {
      if (aSeekFlag == SeekFlag::DidSeek) {
        mHoldTime = unconstrainedCurrentTime;
      } else if (!mPreviousCurrentTime.IsNull()) {
        mHoldTime.SetValue(
            std::min(mPreviousCurrentTime.Value(), TimeDuration(0)));
      } else {
        mHoldTime.SetValue(0);
      }
    } else if (mPlaybackRate != 0.0 && mTimeline &&
               !mTimeline->GetCurrentTimeAsDuration().IsNull()) {
      if (aSeekFlag == SeekFlag::DidSeek && !mHoldTime.IsNull()) {
        mStartTime = StartTimeFromTimelineTime(
            mTimeline->GetCurrentTimeAsDuration().Value(), mHoldTime.Value(),
            mPlaybackRate);
      }
      mHoldTime.SetNull();
    }
  }

  // We must recalculate the current time to take account of any mHoldTime
  // changes the code above made.
  mPreviousCurrentTime = GetCurrentTimeAsDuration();

  bool currentFinishedState = PlayState() == AnimationPlayState::Finished;
  if (currentFinishedState && !mFinishedIsResolved) {
    DoFinishNotification(aSyncNotifyFlag);
  } else if (!currentFinishedState && mFinishedIsResolved) {
    ResetFinishedPromise();
  }
}

void Animation::UpdateEffect(PostRestyleMode aPostRestyle) {
  if (mEffect) {
    UpdateRelevance();

    KeyframeEffect* keyframeEffect = mEffect->AsKeyframeEffect();
    if (keyframeEffect) {
      keyframeEffect->NotifyAnimationTimingUpdated(aPostRestyle);
    }
  }
}

void Animation::FlushUnanimatedStyle() const {
  if (Document* doc = GetRenderedDocument()) {
    doc->FlushPendingNotifications(
        ChangesToFlush(FlushType::Style, false /* flush animations */));
  }
}

void Animation::PostUpdate() {
  if (!mEffect) {
    return;
  }

  KeyframeEffect* keyframeEffect = mEffect->AsKeyframeEffect();
  if (!keyframeEffect) {
    return;
  }
  keyframeEffect->RequestRestyle(EffectCompositor::RestyleType::Layer);
}

void Animation::CancelPendingTasks() {
  mPendingState = PendingState::NotPending;
}

// https://drafts.csswg.org/web-animations/#reset-an-animations-pending-tasks
void Animation::ResetPendingTasks() {
  if (!Pending()) {
    return;
  }

  CancelPendingTasks();
  ApplyPendingPlaybackRate();

  if (mReady) {
    mReady->MaybeReject(NS_ERROR_DOM_ABORT_ERR);
    MOZ_ALWAYS_TRUE(mReady->SetAnyPromiseIsHandled());
    mReady = nullptr;
  }
}

// https://drafts.csswg.org/web-animations-2/#at-progress-timeline-boundary
/* static*/ Animation::ProgressTimelinePosition
Animation::AtProgressTimelineBoundary(
    const Nullable<TimeDuration>& aTimelineDuration,
    const Nullable<TimeDuration>& aCurrentTime,
    const TimeDuration& aEffectStartTime, const double aPlaybackRate) {
  // Based on changed defined in: https://github.com/w3c/csswg-drafts/pull/6702
  // 1.  If any of the following conditions are true:
  //     * the associated animation's timeline is not a progress-based timeline,
  //     or
  //     * the associated animation's timeline duration is unresolved or zero,
  //     or
  //     * the animation's playback rate is zero
  //     return false
  // Note: We can detect a progress-based timeline by relying on the fact that
  // monotonic timelines (i.e. non-progress-based timelines) have an unresolved
  // timeline duration.
  if (aTimelineDuration.IsNull() || aTimelineDuration.Value().IsZero() ||
      aPlaybackRate == 0.0) {
    return ProgressTimelinePosition::NotBoundary;
  }

  // 2.  Let effective start time be the animation's start time if resolved, or
  // zero otherwise.
  const TimeDuration& effectiveStartTime = aEffectStartTime;

  // 3.  Let effective timeline time be (animation's current time / animation's
  // playback rate) + effective start time.
  // Note: we use zero if the current time is unresolved. See the spec issue:
  // https://github.com/w3c/csswg-drafts/issues/7458
  const TimeDuration effectiveTimelineTime =
      (aCurrentTime.IsNull()
           ? TimeDuration()
           : aCurrentTime.Value().MultDouble(1.0 / aPlaybackRate)) +
      effectiveStartTime;

  // 4.  Let effective timeline progress be (effective timeline time / timeline
  // duration)
  // 5.  If effective timeline progress is 0 or 1, return true,
  // We avoid the division here but it is effectively the same as 4 & 5 above.
  return effectiveTimelineTime.IsZero() ||
                 (AnimationUtils::IsWithinAnimationTimeTolerance(
                     effectiveTimelineTime, aTimelineDuration.Value()))
             ? ProgressTimelinePosition::Boundary
             : ProgressTimelinePosition::NotBoundary;
}

StickyTimeDuration Animation::EffectEnd() const {
  if (!mEffect) {
    return StickyTimeDuration(0);
  }

  return mEffect->NormalizedTiming().EndTime();
}

Document* Animation::GetRenderedDocument() const {
  if (!mEffect || !mEffect->AsKeyframeEffect()) {
    return nullptr;
  }

  return mEffect->AsKeyframeEffect()->GetRenderedDocument();
}

Document* Animation::GetTimelineDocument() const {
  return mTimeline ? mTimeline->GetDocument() : nullptr;
}

void Animation::UpdateScrollTimelineAnimationTracker(
    AnimationTimeline* aOldTimeline, AnimationTimeline* aNewTimeline) {
  // If we are still in pending, we may have to move this animation into the
  // correct animation tracker.
  Document* doc = GetRenderedDocument();
  if (!doc || !Pending()) {
    return;
  }

  const bool fromFiniteTimeline =
      aOldTimeline && !aOldTimeline->IsMonotonicallyIncreasing();
  const bool toFiniteTimeline =
      aNewTimeline && !aNewTimeline->IsMonotonicallyIncreasing();
  if (fromFiniteTimeline == toFiniteTimeline) {
    return;
  }

  if (toFiniteTimeline) {
    doc->GetOrCreateScrollTimelineAnimationTracker()->AddPending(*this);
  } else {
    // From scroll-timeline to null/document-timeline
    if (auto* tracker = doc->GetScrollTimelineAnimationTracker()) {
      tracker->RemovePending(*this);
    }
    EnsurePaintIsScheduled(*doc);
  }
}

class AsyncFinishNotification : public MicroTaskRunnable {
 public:
  explicit AsyncFinishNotification(Animation* aAnimation)
      : mAnimation(aAnimation) {}

  virtual void Run(AutoSlowOperation& aAso) override {
    mAnimation->DoFinishNotificationImmediately(this);
    mAnimation = nullptr;
  }

  virtual bool Suppressed() override {
    nsIGlobalObject* global = mAnimation->GetOwnerGlobal();
    return global && global->IsInSyncOperation();
  }

 private:
  RefPtr<Animation> mAnimation;
};

void Animation::DoFinishNotification(SyncNotifyFlag aSyncNotifyFlag) {
  CycleCollectedJSContext* context = CycleCollectedJSContext::Get();

  if (aSyncNotifyFlag == SyncNotifyFlag::Sync) {
    DoFinishNotificationImmediately();
  } else if (!mFinishNotificationTask) {
    RefPtr<MicroTaskRunnable> runnable = new AsyncFinishNotification(this);
    context->DispatchToMicroTask(do_AddRef(runnable));
    mFinishNotificationTask = std::move(runnable);
  }
}

void Animation::ResetFinishedPromise() {
  mFinishedIsResolved = false;
  mFinished = nullptr;
}

void Animation::MaybeResolveFinishedPromise() {
  if (mFinished) {
    mFinished->MaybeResolve(this);
  }
  mFinishedIsResolved = true;
}

void Animation::DoFinishNotificationImmediately(MicroTaskRunnable* aAsync) {
  if (aAsync && aAsync != mFinishNotificationTask) {
    return;
  }

  mFinishNotificationTask = nullptr;

  if (PlayState() != AnimationPlayState::Finished) {
    return;
  }

  MaybeResolveFinishedPromise();

  QueuePlaybackEvent(nsGkAtoms::onfinish,
                     AnimationTimeToTimeStamp(EffectEnd()));
}

void Animation::QueuePlaybackEvent(nsAtom* aOnEvent,
                                   TimeStamp&& aScheduledEventTime) {
  // Use document for timing.
  // https://drafts.csswg.org/web-animations-1/#document-for-timing
  Document* doc = GetTimelineDocument();
  if (!doc) {
    return;
  }

  nsPresContext* presContext = doc->GetPresContext();
  if (!presContext) {
    return;
  }

  Nullable<double> currentTime;
  if (aOnEvent == nsGkAtoms::onfinish || aOnEvent == nsGkAtoms::onremove) {
    currentTime = GetCurrentTimeAsDouble();
  }

  Nullable<double> timelineTime;
  if (mTimeline) {
    timelineTime = mTimeline->GetCurrentTimeAsDouble();
  }

  presContext->AnimationEventDispatcher()->QueueEvent(
      AnimationEventInfo(aOnEvent, currentTime, timelineTime,
                         std::move(aScheduledEventTime), this));
}

bool Animation::IsRunningOnCompositor() const {
  return mEffect && mEffect->AsKeyframeEffect() &&
         mEffect->AsKeyframeEffect()->IsRunningOnCompositor();
}

bool Animation::HasCurrentEffect() const {
  return GetEffect() && GetEffect()->IsCurrent();
}

bool Animation::IsInEffect() const {
  return GetEffect() && GetEffect()->IsInEffect();
}

void Animation::SetHiddenByContentVisibility(bool hidden) {
  if (mHiddenByContentVisibility == hidden) {
    return;
  }

  mHiddenByContentVisibility = hidden;

  if (!GetTimeline()) {
    return;
  }

  GetTimeline()->NotifyAnimationContentVisibilityChanged(this, !hidden);
}

void Animation::UpdateHiddenByContentVisibility() {
  // To be consistent with nsIFrame::UpdateAnimationVisibility, here we only
  // deal with CSSAnimation and CSSTransition.
  if (!AsCSSAnimation() && !AsCSSTransition()) {
    return;
  }
  NonOwningAnimationTarget target = GetTargetForAnimation();
  if (!target) {
    return;
  }
  // If a CSS animation or CSS transition is no longer associated with an owning
  // element, it behaves like a programmatic web animation, c-v shouldn't hide
  // it.
  bool hasOwningElement = IsMarkupAnimation(AsCSSAnimation()) ||
                          IsMarkupAnimation(AsCSSTransition());
  if (auto* frame = target.mElement->GetPrimaryFrame()) {
    SetHiddenByContentVisibility(
        hasOwningElement && frame->IsHiddenByContentVisibilityOnAnyAncestor());
  }
}

StickyTimeDuration Animation::IntervalStartTime(
    const StickyTimeDuration& aActiveDuration) const {
  MOZ_ASSERT(AsCSSTransition() || AsCSSAnimation(),
             "Should be called for CSS animations or transitions");
  static constexpr StickyTimeDuration zeroDuration = StickyTimeDuration();
  return std::max(
      std::min(StickyTimeDuration(-mEffect->NormalizedTiming().Delay()),
               aActiveDuration),
      zeroDuration);
}

// Later side of the elapsed time range reported in CSS Animations and CSS
// Transitions events.
//
// https://drafts.csswg.org/css-animations-2/#interval-end
// https://drafts.csswg.org/css-transitions-2/#interval-end
StickyTimeDuration Animation::IntervalEndTime(
    const StickyTimeDuration& aActiveDuration) const {
  MOZ_ASSERT(AsCSSTransition() || AsCSSAnimation(),
             "Should be called for CSS animations or transitions");

  static constexpr StickyTimeDuration zeroDuration = StickyTimeDuration();
  const StickyTimeDuration& effectEnd = EffectEnd();

  // If both "associated effect end" and "start delay" are Infinity, we skip it
  // because we will get NaN when computing "Infinity - Infinity", and
  // using NaN in std::min or std::max is undefined.
  if (MOZ_UNLIKELY(effectEnd == TimeDuration::Forever() &&
                   effectEnd == mEffect->NormalizedTiming().Delay())) {
    // Note: If we use TimeDuration::Forever(), within our animation event
    // handling, we'd end up turning that into a null TimeStamp which can causes
    // errors if we try to do any arithmetic with it. Given that we should never
    // end up _using_ the interval end time. So returning zeroDuration here is
    // probably fine.
    return zeroDuration;
  }

  return std::max(std::min(effectEnd - mEffect->NormalizedTiming().Delay(),
                           aActiveDuration),
                  zeroDuration);
}

}  // namespace mozilla::dom